Heating-element-controlling device



P. M. MUELLER.

HEATING ELEMENT CONTROLLING DEVICE.

APPLICATION men MAR. 24. 192.0.

Patented Au 23, 1921.

INVENTOR W 2% A llorney UNITED STATES PATENT .OFFICE.

I PAUL M. MUELLER, or. ERIE, PENNSYLVANIA, ASSIGNOR T0 AMEaioANTEEILIZER COMPANY, 0E ERIE, PENNSYLVANIA, A CORPORATION or PENNSYLVANIA,

HEATINe-ELEMENT-ooNrRoLLINe DEVICE.

Patented Aug. 23 1921.

Application filed. March 24, 1920. Serial No. 368,246.

To all w 710m it may concern:

Be it known that I, PAUL MANNING MUELLER, a citizen of the UnitedStates, residing at Erie, in the county of Erie and State ofPennsylvania, have invented new and useful Improvements in a Heating-Element-Controlling Device, of which the following is a specification.

TVith electric heating elements which are used for heating liquidsdifliculty is experienced when the element is accidentally uncoveredthrough an excess of heat. Inasmuch'as it is the heating element that issubject to such injury it is desirable that the heat of the elementitself should operate as directly as possible on the'means for varyingthe current on the element so as to relieve it of the excess heat.accomplished through fuses but this manner of obviating the difficultynecessitates a rather inconvenient re-assembling of the parts, that is,the placing of new fuses.

In this invention the electric current is cut ofi from the heatingelement through a switch which is preferably directly operated by'althermal element which is subjected as directly as possible to thermalchanges in.

the heating element and all that is necessary in order to re-set thedevice is to re-set the switch after it has been thrown out through theaction of the thermal element acting under the influence of the heatingelement.

The invention is illustrated in the accompanying drawings as followsFigure 1 shows a central section through the device.

Fig. 2 an end View of the heatlng element.

Fig. 3 a perspective View, partly 1n section, of the switch mechanism.

Fig.4 a plan view ofthe switch.

1 marks a receptacle which is adapted to retain a liquid, 2 a heatingelement, 3 a hollow plug in which the heating element is secured, 4external screw threads on the plug, and 5 a nut by means of which theplug is secured in thewalls of the recepta- 'cle, the usual, packing,(not shown) being ordinarily supplied.

The heating element has the usual casing 6 in which the heating "elementproper is placed. The heating element may be of any of the well-knowndesigns. As shown it has the insulating core 7 and windings 8 and 9. Thewindings 8 and 9 are connected by the extensions 10 with the plugs 11which lead This has been to one side of the main circuit and the coilslead through a connection 12 to a contact post 13 which connects to aswitch table 14. Contact fingers 15 are carried by a swinging switchlever 16 into andout of contact with the bracket 14. The switch lever ispivoted by means of a pin 17 on a post 18. Thepost 18 is carried by aninsulated block 19. The insulated block is secured to lugs 19 extendingfrom the hollow plug 3'. The post 18 is connected with a plug 20 andthisplu is connected with the other side ofthefline from the plugs 11, thelines being carried with the contact bracket 14. A thermal element 27 ismounted in a receptacle 28 arranged in contact with the case 2 andextending along the case. One end of this receptacle 28 opens into thehollow plug 3.

The thermal element 27 is secured at the outer end of the receptacle 28by -means of blocks 29 which form a closure for the end ofthereceptacle28 and at the same time hold the thermal elementin'position lengthwise of the receptacle and case. The end 30 of thethermal elementat normal temperature engages the insulated block '25 onthe switch lever and holds the switch fingers 15 in contact withthetable 14. When, however, the thermal element is heated above the normaltemperature it bends, thus-disengaging the lever 16 which acting underthe influence of the "spring 26 swings so as to carry the contactfingers 15 out of contact withthe table 14, thus opening the circuit.

I When the parts are assembled and the thermal element is initiallyheated it bends so as to contact the wall remote from the heatingelement and in thiscposition the metal of the heating element isstretched or strained so thatwhen it'returns on cooling it withcertainty reaches aposition to; 0perate to hold the switch lever inposition. After this initial heating the thermal ele ment is notordinarily subjected to suflicient heat to bend it to a point where itwill reach the extreme wall of the inclosing tube. By using this meansof assembling the thermal element is automatically adjusted regardlessof its initial shape.

The thermal element is one of ordinary commercial type usually formed oftwo kinds of metal having different qualities of expansion. I prefer tocoat this element with some black coloring matter so that variations intemperature along the case are not only communicated to the elementthrough the block 29 but also through radiation.

WVhat I claim as new is z- 1. I11 a heating element controlling device,the combination of a heating element; an inclosing casing; a thermallysensitive element in direct thermal relation with the casing; aconductor leading to the heating element; a switch in the conductor; andmeans controlled by the thermal element opening the switch.

2. In a heating element controlling device, the combination of a heatingelement; an inclosing casing; a thermally sensitive element; a thermalelement receptacle in contact with the casing; a conductor leading tothe heating element; a switch in the conductor; and means controlled bythe thermal element opening the switch.

'3. In' a heating element controlling device, the combination of aheating element; an inclosing casing; a thermally sensitive elementextending lengthwise of the heating element; a thermal elementreceptacle in contact with the casing in which the thermal element isarranged; a conductor leading to the element; a switch in the conductor;and means controlled by the thermal element opening the switch.

4. In a heating element controlling device, the combination of a heatingelement; an inclosing'casing; a thermally sensitive element extendinglengthwise of the casing; a thermal element receptacle in which thethermal element is arranged, said. receptacle limiting the movement ofthe thermal element; a conductor leading to the heating element; aswitch in the conductor; and means controlled by the thermal elementopening the switch.

5. In a heating element controlling device, the combination of a heatingelement;

an inclosing casing; a thermally sensitive element formed of two metalsof varying expansive quality; a thermal element receptacle in which thethermal element is arranged extending along and in contact with thecasing; a conductor leading to the heating element; a switch in theconductor; and means controlled by the thermal element opening theswitch.

6. In a heating element controlling device, the combination of a heatingelement; an inclosing casing; a thermally sensitive element in directthermal relation with the casing; a conductor leading to the heatingelement; a switch in the conductor; and means controlled by the thermalelement opening the switch, said thermal element acting directly on themovable element of the switch.

7. In a heating element controlling device, the combination of a heatingelement; an inclosing casing; a thermally sensitive element extendinglengthwise of the heating element; a thermal element receptacle incontact with the casing in which the thermal element is arranged; aconductor leading to the element; a switch in the conductor; and meanscontrolled by the thermal element opening the switch, said thermalelement acting directly on the movable element of the switch.

8. In a heating element controlling device, the combination oil a hollowplug; a heating element leading from the plug; an inclosing casingsecured to the plug; a thermally sensitive element in direct thermalrelation with the casing; an inclosing receptacle for said thermallysensitive element leading to the hollow plug; a conductor leading to theheating element; a switch in the conductor; and means controlleddirectly by the thermal element opening the switch.

9. In a heating element controlling de vice, the combination of a hollowplug; a heating element leading from the plug; an inclosing easingsecured to the plug and opening into the interior of the plug; athermally sensitive element extending lengthwise of the case and intothe hollow plug; an inclosing receptacle for the thermal element; aswitch carried by the plug comprising a spring-actuated lever engagingthe thermal element when the thermal element is subjected to normaltemperature and adapted to be released by a movement'o't the thermalelement to open the switch; and a conductor leading to the heatingelcment through the switch.

10. In a heating element controlling device, the combinationof a heatingelevent; an inclosing casing; a thermally sensitive element extendingalong the casing, said element having a black coating for the purposedescribed; and an inclosing receptacle for the thermally sensitiveelement.

In testimony whereof I have hereunto set my hand.

PAUL MUELLER.

